ghsa-2rf4-w4q3-rjcw
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
nbd: fix uaf in nbd_genl_connect() error path
There is a use-after-free issue in nbd:
block nbd6: Receive control failed (result -104) block nbd6: shutting down sockets ================================================================== BUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022 Write of size 4 at addr ffff8880295de478 by task kworker/u33:0/67
CPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: nbd6-recv recv_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] recv_work+0x694/0xa80 drivers/block/nbd.c:1022 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
nbd_genl_connect() does not properly stop the device on certain error paths after nbd_start_device() has been called. This causes the error path to put nbd->config while recv_work continue to use the config after putting it, leading to use-after-free in recv_work.
This patch moves nbd_start_device() after the backend file creation.
{
"affected": [],
"aliases": [
"CVE-2025-38443"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-25T16:15:29Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: fix uaf in nbd_genl_connect() error path\n\nThere is a use-after-free issue in nbd:\n\nblock nbd6: Receive control failed (result -104)\nblock nbd6: shutting down sockets\n==================================================================\nBUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022\nWrite of size 4 at addr ffff8880295de478 by task kworker/u33:0/67\n\nCPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nWorkqueue: nbd6-recv recv_work\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:408 [inline]\n print_report+0xc3/0x670 mm/kasan/report.c:521\n kasan_report+0xe0/0x110 mm/kasan/report.c:634\n check_region_inline mm/kasan/generic.c:183 [inline]\n kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189\n instrument_atomic_read_write include/linux/instrumented.h:96 [inline]\n atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]\n recv_work+0x694/0xa80 drivers/block/nbd.c:1022\n process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238\n process_scheduled_works kernel/workqueue.c:3319 [inline]\n worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400\n kthread+0x3c2/0x780 kernel/kthread.c:464\n ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nnbd_genl_connect() does not properly stop the device on certain\nerror paths after nbd_start_device() has been called. This causes\nthe error path to put nbd-\u003econfig while recv_work continue to use\nthe config after putting it, leading to use-after-free in recv_work.\n\nThis patch moves nbd_start_device() after the backend file creation.",
"id": "GHSA-2rf4-w4q3-rjcw",
"modified": "2025-07-25T18:30:39Z",
"published": "2025-07-25T18:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38443"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/002aca89753f666d878ca0eb8584c372684ac4ba"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8586552df591e0a367eff44af0c586213eeecc3f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/91fa560c73a8126868848ed6cd70607cbf8d87e2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aa9552438ebf015fc5f9f890dbfe39f0c53cf37e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cb121c47f364b51776c4db904a6a5a90ab0a7ec5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d46186eb7bbd9a11c145120f2d77effa8d4d44c2"
}
],
"schema_version": "1.4.0",
"severity": []
}
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